Sound is defined as a variation of acoustic pressure due to air vibrations. In the case of human voice, vocal cords vibrate to create motion in the air. During a vocal sound take, many elements form what you could call the sound chain. This chain allows the conversion of the acoustic energy of a voice into electrical energy thanks to the microphone. The sound card or audio interface will convert this electrical signal in digital information so the sound can be manipulated from your computer through your favorite editing/mix software. When you hear the outcome, the sound will flow through these parts and to your speakers or your headphones So it is of primary importance to choose appropriate gear to build your sound chain not to alter the take in its multiple conversions.
This article is there to introduce you some keys for your equipment choice, in the perspective of a professional sound take. We will mainly focus on vocal sound takes, meant for audiovisual projects including commercials and radio.
Probably one of the most important piece for your vocal takes. Indeed, it is the device that will capture your voice with maximum fidelity to change it into an electrical signal. Many capture technologies are especially adapted to various uses such as singing, dubbing a movie… To record your voice, the most common way would be using a static, large diaphragm microphone, also called condenser microphone.
These mics are mainly used for vocal sound takes or for instruments in studio. You have probably seen one of those before, they are quite large and often place behind a pop filter. This type of microphone can be bought starting from 50 euros and up to 10 000 euros or over.
So there are several criteria you need to be aware of to make your choice:
– Directivity: this is the way your mic captures the sound. Here we will choose cardioid to capture the sound from the front of the mic with a natural result.
– Sensitivity: another criteria to consider, this is the output level of your microphone. Expressed in mV/Pa (milli-volt per Pascal), it indicates the electric power delivered by the mic for an acoustic pressure of 1 pascal. Choose a sensitivity high enough for vocal takes so you don’t require to much effort from the other pieces of the sound chain.
– The bandwidth: this is the range of the audio spectrum that your mic is able to capture. The audible spectrum goes from 20 Hz to 20 000 Hz (20 kHz) for most people. The human voice generally lies between 70 Hz and 12 kHz. Make sure to choose a mic able to capture at least these frequencies. The larger the bandwidth, the more precise and clear the sound.
– The response curve: often given with a graph. Depending on the frequencies of the bandwidth, mics don’t respond the same way. Indeed some mics tend to boost specific parts of the audible spectrum compared to others. So choose the flatest curve for a mic working well with any voice.
Advice for your purchase: You can make a safe bet by choosing a well-known brand used by professionals. A benchmark for recording voice overs: Neumann, AKG, Audio-technica, Blue microphones, Sennheiser, Shure, Electro-voice…
Few iconic models: Neumann U87, AKG C414, AKG C314, Neumann TLM 103, Audio-Technica 4033, Blue Mini Bottle…
Another key element of your sound chain is the audio interface. It changes the electrical signal received from the mic into digital information. That conversion allows your computer to save, edit, mix any audio take. The interface will work the same way to change a « digitalised » sound in electrical signal, then in acoustic signal, spread through you speakers or headphones.
There is a great number of interfaces available, of all sizes and for all budgets. It is sometimes hard to pick one out of this huge variety, so here are the main criteria you consider:
– The type of input: Choose an interface featuring at least one XLR input for the microphone. This format is the professional one used to connex a microphone to any device.
– The type of output: During the take, you must be able to listen to your voice as capture by the mic. Therefore, your interface should feature an output for headphones, with a volume knob. Furthermore, additional outputs for monitoring speakers (jacks TRS or XLX) would be handy.
– A quality pre-amplifier: To deal with the signal received from a microphone, it must be pre-amplified. A mic preamp allows to boost the voltage from the mic (only few mV) to a scale measured in Volts (V). The quality of your preamp has an impact on the quality of your sound in general. A good preamp should give you a gain of 40/50 dB at least. The preamp must also feature a phantom power (+48V) to supply power to your condenser mic (or static mic).
– Sample rate and resolution : These are the info that tell the quality of the analog-to-digital conversion. The higher these numbers, the more precise the sound once converted. You need to choose a sample rate reaching at least 96KHz and a resolution reaching 24bits.
Just a tip : For vocal takes, you should likely look for a simple interface of good quality, rather than a more sophisticated one for the same price.
Few brands worth looking at: Focusrite, Steinberg, Motu, Universal Audio, RME…
The software sequencer:
After the conversion of the sound from audio to digital information, the sound must now be saved on your computer. That is exactly what a sequencing software is for.
There are many different software available, with various functionalities and features…
But, regarding the audio editing, they remain pretty much all the same. The choice of a software among others will therefore be entirely yours, depending on your needs and how convenient you will find each.
Explore the different offers by downloading trial versions so you can have an idea of how it feels with in real work context. Apart from that, you will find many tutorials online for the most commonly used software, this will help not being lost it the huge amount of options these softwares feature.
The most sofisticated sofwares are not free of course and most of time PC and Mac compatible. We strongly advice paying the licence of the software, rather that using a crack version. It is not only more honest, you will also face less bugs and will not risk the heavy fine in case of control.
Few must-know softare:
– Avid Protools
– Logic Pro (uniquement Mac)
– Digital Performer
During recording sessions, using headphones is non-negotiable. Indeed, this avoids that the sound from speakers is captured by the mic, which ruins a vocal take. The right choice of headphones mainly depends on the one who will use it. Closed, over-ear headphones of good quality with a flat response curve would be handy to hear every detail of our vocal take.
– The XLR cable(s) : It will make the connection between your mic and the soundcard. Choose a length that is in line with the position of the mic (3 to 5 meters might be enough).
– The mic stand: It will maintain the mic in a fixed position. A stable and resistant one will prevent your mic from moving once oriented.
You are now aware of the basics for a good vocal take. Of course, the choice of the equipment must be coherent. There is no point buying a Neumann U87 if you are using a low-end audio interface …